They propose to 1) Identify new antigens and epitopes from malaria liver stages (Exo-erythrocytic forms (EEF). Immunization with radiation-attenuated sporozoites leads to sterile immunity, and the effector mechanisms are antibodies, cytotoxic lymphocytes (CTL) and lymophokines. In the blood circulation, antibodies attach the incoming sporozoites. If some escape and enter hepatocytes, the developing EEF can only be destroyed by T lymphocytes or by their products. Though very desirable, the systematic identification of proteins synthesized by sporozoites and carried into the EEF, or of EEF-specific proteins, has been hindered by difficulties in obtaining purified preparations of these parasite stages. They have constructed rodent malaria parasites (Plasmodium berghei) expressing GFP, the green fluorescent protein. FAC sorting will permit the purification of the highly fluorescent sporozoites from the contaminating material in the salivary glands of mosquitoes, and separation of the EEF from the vast numbers of non-infected hepatocytes.